Oil Change on a Mercedes 300SD

Performing an oil change on a 81-85 Mercedes-Benz 300SD is probably the easiest maintenance job you'll ever do on your Benz. I've done oil changes under extreme conditions, like at Wal-Mart parking lot while my wife is getting her hair done. You must do this job every 5,000 miles, some suggest every 3,000, and some nutjobs change oil every 1,500-2,000, which would be every month the way I drive. I do my oil changes every couple-three months, or 4,000 miles. It's a beautiful day, as you can see, so I'm going to crank one out. Some general observations before I begin:
  • You must perform oil changes regularly;
  • I'd recommend using oil with soot suspension, like Shell Rotella;
  • Diesel oil will get very black almost immediately after you change it;
  • I use 15W-40 year round and I am very happy with it.
Here's my standard list of items I use during every oil change:
  • Absorbent shop towels;
  • A 13 mm socket;
  • The fuel filter, the rubber ring, and the copper gasket;
  • Two gallons of Shell Rotella 15W-40;
  • Oil pan for collection of waste oil;
  • Gloves.
First I let the car run until the temp sensor is at 80. Then I pop the hood and raise it to the 90 angle. People freak out when they see that. Position your Wal-Mart-bought oil pan under the car. Here's what it looks like. Locate the oil drain plug. Take it out with a 13 mm wrench. Be careful - you might strip the plug if it's been screwed in too tight. I've done that before. I had to remedy that by going to a nearest tire shop, elevating the car, and paying the guy to take it out. The plug feels like it's not a 13, but a 12.8 - the wrench is a little loose on it. Let the oil drip out. This is when I go have a sandwich. After the oil is done dripping, focus your attention and your 13 mm socket on the oil filter housing located by the firewall on the driver's side. Unscrew the two nuts on the sides. I can't help but notice that crafty Germans etched the filter part number and the outline of the filter on the lid. Wow. Pull out the lid. Peek inside the housing. Remove the old filter. Sit it on the oil collection pan to drain. Insert the new filter into the housing. I've used both Mann (OEM) and Champion (non-OEM, bought at AdvanceParts) filters and they both seem to work just fine. This time I've stocked up on Mann's. Dive under the car again and screw in the oil plug. Don't forget the copper gasket. Don't overtighten. My mechanic says that nothing of this car has to be tightened with both hands. Insert the funnel into the oil hole in the valve cover: Time to give the 617 its honey. Pour about a gallon and a quarter. Use the dipstick to gauge how much oil you are adding. When I poured used oil into empty Rotella canisters, I got about 1.3 gallons. Clean up and you're done!


Blogger reckless rogue said...

Good stuff. I've found the FRAM and other non-OEM filters are ok as well. I FEEL better going with the OEM stuff though.

I use an extender to get the oil filter nuts off just to prevent any damage to the rather fragile vacuum lines that are closeby.

Other than that, I don't worry too much about torque specs. Like you said, nothing has to be torqued down hard; that goes for the wheel lugs too!! The spec is actually around 80 Ft Lbs. Nothing pisses me off more than to watch an uneducated grease monkey take his air wrench (set at like 400) and torque wheel lugs all the way down. So much damage is caused this way it isn't even funny. I don't let anybody touch my wheels anymore because of this.

1/27/2006 11:54:00 AM  
Blogger Gunnar Heinrich said...

Great column. Your step by step instruction was excellent. If I had a 300SD, I'd be tempted to go to The Walmart, buy the right stuff and give it a try myself. Though, truth be told, I'd probably still prefer to have the Valvoline guy do the job for $19.99.

Observation- You should replace the hood insulation. This can be done relatively cheaply and is beneficial in many different ways to your car.


1/29/2006 02:11:00 AM  
Anonymous 300SD said...

The Valvoline guys, in my experience, are either freshmen in a local college, or middle-aged men with lack of education; sad but true. They neither want nor need to respect something as remarkable as a 300SD.

The only man in the Midwest I would trust with my car is Frank of Frank's Service in Lansing, Michigan. The guy's been fixing Benz's for 47 years. The Valvoline guys didn't even know how to open the hood.

By the way, you know a W126 enthusiast by the way he opens the hood - both middle fingers on latches, index fingers raising the hood.

Gunnar, thanks for the tip about the hood insulation. That's where my next $100 is going to go, although Frank doesn't believe in the hood insulation.

1/30/2006 10:42:00 AM  
Blogger Gunnar Heinrich said...

My pleasure.

You are correct about the W126 enthusiast mechanic (rare to find an enthusiastic mechanic period). Unless they are opening the hood of a post 1985 W126 S-Class sedan, in which case, they use the little lever that pops out of the grille.

You're probably right about the Valvoline guys.

By the by, how are you maintaining the appearance of your 300SD?


1/30/2006 11:22:00 AM  
Anonymous Greg said...

Hi Max, thanks a lot... for your advice.

As you're a hardcore 300SD enthusiast, you are the correct person to help me in a very important desition that I have to do:

To buy or not to buy a 1981 300SD.

May I email you for detils?



1/30/2006 12:43:00 PM  
Anonymous 300SD said...

The appearance of my 300sd is maintained by washing it every week with automotive soap (1 oun. per gal) and spraying the underbody with a pressure soaker.

While washing, I note any dings/scratches, log them, and when the car is dry, I retouch them with MB paint and lacquer.

When the spring comes, I wash the car once with Dawn soap (blue) to wash off everything, then triple-coat it with teal Zymol, $13.00 at AutoZone.

This spring I might buy a random orbit buffer ($20.00 at Wal-Mart and rubbing compound ($8.00 at a farm supply store) to scrape off winter grime, then 5 coats of Zymol, which works great - water still beading off the August coats.

The engine compartment is inspected every week for leaks/noise. Air filter housing and other large parts are WD-40'd, leaks around valve cover and breather hose wiped. Tire pressure checked, 30 on front, 32 in back.

By the way...

I make sure to leave the cap on the coolant tank LOOSE. If you remember your physics, it doesn't make sense to keep your cooling system pressurized if you live in the Midwest. Water pump problems and leaks are directly related to overpressurized cooling circuit.

1/30/2006 02:45:00 PM  
Blogger Gunnar Heinrich said...


From what I can see, you do a great job in keeping your S-Class looking good.

The dawn soap is not a bad idea to get everything off the car (including old wax). However, it does little favors for the paint job itself.

I suggest one of two options:

1)Use a kind Paint Cleaner. Follow with as many coats of Polish as you would like. Lastly, add however many coats of wax you deem necessary.

2)Use regular car soap and mix in Paint Cleaner. Wash normally. Towel dry. Then apply polish and wax.

If you are using the two-in-one Zymol hybrid wax that is a blue liquid that comes in a squeeze bottle and is available everywhere, I recommend that you change your product.

I have rarely found polish-waxes or cleaning-waxes to be successful at doing either job (cleaning the paint or protecting it) including that specific Zymol product.

I suggest the following:

Zymol Waxes (www.zymol.com) - that is their true waxes that are Carnuba based and come in little tubs, are the best waxes on the market. Their regular line of Carnuba waxes is about $40 per tub.

They also have custom waxes developed for Concours cars that you must apply using your hand that can cost upwards to over $1,000 per tub.

Zymol's waxes are superior, except for one draw back and that is that they are labor intensive to apply and then buff out.

The best choice I have encountered is AutoGlym (www.autoglym.co.uk). They do an even better job of making one's paint job shine and are far less labor intensive. As a matter of fact, it is the easiest wax I have ever applied. They also offer paint cleaner and polishes. A bottle of wax costs $28 (last time I checked).

If you want the best for car's paint, I would get a bottle of paint cleaner, polish, and wax from either Zymol or Autoglym. A cheaper, but not as good alternative is to get the three compounds from Meguiars at Autozone.

I hope you find this helpful.


1/30/2006 06:13:00 PM  
Anonymous 300SD said...

You're right, carnauba-based waxes are a gigantic pain in the ass to apply and buff. Also, the ambiant temp's got to be right.

I've always applied wax manually. Have you ever used mechanical tools?

1/30/2006 10:56:00 PM  
Blogger Gunnar Heinrich said...

The first time I tried using an orbital buffer, the wax seemed to go everywhere in the garage except on the car.

The by-hand method may be slow, but for me it assures the highest accuracy in putting the wax where it needs to be.

Plus with Autoglym it is painless. The wax is not Carnuba based, but it seems to make the paint look just as good. Though Carnuba waxes are probably more durable.


1/30/2006 11:35:00 PM  
Blogger reckless rogue said...

I've found the only way to get a high-quality polish and wax job is to nearly break your arm in the buffing process.

Of course, I think the original owners of our prized automobiles most likely did not have to worry about getting their exercise this way.

1/31/2006 11:34:00 AM  
Blogger Gunnar Heinrich said...

Depending on the condition of your 300SD's paint, this could be true. Something about the 80s diesel Benzes can lead them to have really oxidized paint that means you could polish forever and feel like you're getting no where.

Short of having a new paint job, your best bet is to go to a body shop and have them buff the car's paint with polish to take down a layer of paint and then you take over with polish application and then wax. Such measures would make for much easier waxing.

And again, this Autoglym stuff is really easy to put on and buff off.


1/31/2006 12:47:00 PM  
Blogger reckless rogue said...

As far as domestic polishes are concerned, I've had very good results with Zaino's products. Maguires is just awful and is a total waste of money and time.

2/01/2006 09:28:00 AM  
Blogger Gunnar Heinrich said...

Honestly, I have found Meguiars to produce some very good results on cars. If one uses their cleaner, polish, and wax liquid applications - on most paint jobs it will make the car shine nicely.


2/01/2006 01:52:00 PM  
Blogger reckless rogue said...

Gunnar, I guess we can agree to disagree on that one. Have you ever tried Zaino's?

2/01/2006 02:22:00 PM  
Anonymous 300SD said...

I've read plenty of good things about Zaino's. A bit pricey, though. And kind of complicated.

2/01/2006 05:39:00 PM  
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8/21/2014 05:11:00 AM  
Blogger Chris Delgadillo said...

What can cause a 300sd to lose all its oil while driving? How would you diy the repairs?

3/24/2015 02:56:00 AM  
Blogger steve cook said...

I am the owner of an 83 300SD, and want to mention the oil cooler regarding oil changes. If you loosen the lower line on the oil cooler, and put a drain tub under it, you'll see just under, or over a QUART of dirty oil come out. I don't like leaving that much dirty oil in the system, so I drain it also.
I use mobil delvac 15-40, it is only 10.97 a gallon these days at Walmart.

Steve IN AZ

10/15/2016 03:24:00 PM  
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4/17/2018 05:51:00 PM  
Blogger Orly said...

Did I miss on your instructions a reference to the rubber seal for the oil filter?

11/17/2018 07:09:00 AM  

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